MODALS VERB

 MODALS VERB: MUST, MIGHT, AND MAY.

There are many modal verbs in English. But Today we are going to take a look at the rules on the use of the modal verbs “must”, “may” and “might”.

MUST 

AFFIRMATIVE	NEGATIVE
MUST	MUST NOT

The modal verb "must" is used in expressions of obligation and necessity. “Must” means that the obligation to do something comes from the speaker; in other words, there is no rule. In addition, "must" expresses the feelings of the speaker.

For example: 

• “I must stop smoking. It's really bad for my health."

MAY AND MIGHT

AFFIRMATIVE	NEGATIVE
MIGHT	MIGHT NOT
MAY	MAY NOT

First of all, the modal verbs “may” and “might” are used to express that something is possible and both are used in verb tenses related to the present and the future.

FOR EXAMPLE:

• It may be true. 
• He may know.
• Take an umbrella with you. It might be raining later.

Basically, "may" implies that there is a greater chance of something happening than "might" (perhaps 70% vs. 30%).

If you're talking about a situation that isn't real, it's best to use the word "might."

To talk about possible actions or events in the past, use “may have” (“done”) or “might have” (“done”).